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.GF file extension

To open .GF files on Windows, install a TeX distribution that includes METAFONTware tools (for example, TeX Live on Windows).

To open a .gf file, use TeX Live/METAFONT tools such as gftype to inspect it, or convert it to a .pk bitmap font using gftopk. On most systems, .gf is not meant for double-click viewing; it is an intermediate font-output file in TeX workflows.

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Last updated: April 30, 2026 · Reviewed by Julian Stricker

Open on your device

Choose your operating system for a dedicated step-by-step opening guide.

How to open .GF files

Use these platform-specific instructions to open .GF files safely.

Windows

  1. Install a TeX distribution that includes METAFONTware tools (for example, TeX Live on Windows).
  2. Open a Command Prompt in the folder containing the .gf file and run: gftype yourfont.gf to inspect it.
  3. If you need a usable TeX bitmap font, convert it with: gftopk yourfont.gf yourfont.pk
Full Windows guide

Mac

  1. Install TeX Live (MacTeX) so you have the METAFONTware utilities available.
  2. In Terminal, run: gftype yourfont.gf to view/inspect the file contents.
  3. Convert to PK when needed: gftopk yourfont.gf yourfont.pk
Full Mac guide

Linux

  1. Install TeX Live binaries/tools from your distribution repositories so gftype/gftopk are available.
  2. Run: gftype yourfont.gf to inspect the GF file and confirm it is valid.
  3. Convert to a PK font if required by your TeX/DVI workflow: gftopk yourfont.gf yourfont.pk
Full Linux guide

iOS

  1. iOS does not commonly provide TeX/METAFONT utilities; transfer the .gf file to a desktop system with TeX Live to inspect (gftype) or convert (gftopk) it.
Full iOS guide

Android

  1. Android does not commonly include TeX/METAFONT utilities; move the .gf file to a desktop system with TeX Live to inspect it with gftype or convert it with gftopk.
Full Android guide

Security notes

  • GF files are bitmap font data and do not contain macros/scripts in the way TeX input files do, but opening malformed files in parsers/converters can still trigger bugs; only process .gf files from sources you trust.
  • Prefer using well-maintained TeX distributions (e.g., TeX Live tools) for reading/converting GF, since these are the standard utilities referenced for handling the format.
  • If a .gf file arrives unexpectedly, treat it as an unusual build artifact: confirm the sender and intended use before running conversion tools on it.

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Can't open this file?

These are the most common causes and fixes when .GF files fail to open.

Common reasons

  • Double-clicking the .gf file does nothing or opens the wrong app
  • TeX/DVI tools cannot use the font (missing .pk)
  • gftype/gftopk reports errors or the output looks corrupted

Fix steps

  1. Use command-line tools: run gftype to inspect the file, or gftopk to convert it to .pk.
  2. If you need the font for TeX, ensure your TeX distribution is installed and its binaries are on your PATH.

OS-specific troubleshooting

What is a .GF file?

A .gf file is a METAFONT output format called a “generic font” file, containing raster (bitmap) font data. The GF format has a defined structure (preamble, character data, postamble) and is primarily used as an intermediate representation. Modern TeX workflows commonly convert GF to PK (packed font) for use by DVI-reading programs.

Background

In TeX/METAFONT workflows, METAFONT produces bitmap fonts and related files; the raster output is written as NAME.NNNNgf (a GF file), alongside a metrics file (TFM). The GF file is the “generic font” output: a structured, machine-readable bitmap font representation.

Because many TeX/DVI programs historically relied on the packed bitmap format, a common step is converting GF to PK using the gftopk utility. In practical terms, most users encounter .gf files as build artifacts produced during font generation, not as files intended to be opened in general-purpose apps.

If you need to understand or verify what is inside a .gf file, the gftype tool translates/prints information from GF files for inspection and troubleshooting. The canonical, detailed definition of the format is documented in Knuth’s Metafontware (GFtype documentation).

Common MIME types: application/x-tex-gf

Further reading

Authoritative resources for more details on the .GF format.

Common .GF issues

Double-clicking the .gf file does nothing or opens the wrong app

.gf is a specialized METAFONT bitmap output and is not typically associated with desktop GUI apps.

  1. Use command-line tools: run gftype to inspect the file, or gftopk to convert it to .pk.
  2. If you need the font for TeX, ensure your TeX distribution is installed and its binaries are on your PATH.

TeX/DVI tools cannot use the font (missing .pk)

Many workflows expect PK as the canonical TeX bitmap font format; GF is often an intermediate output.

  1. Convert the GF file to PK using: gftopk yourfont.gf yourfont.pk
  2. Confirm the PK font is placed where your TeX/DVI environment searches for bitmap fonts.

gftype/gftopk reports errors or the output looks corrupted

The GF file may be incomplete, not actually a GF file, or produced by a mismatched/incorrect METAFONT run.

  1. Verify the file really is METAFONT output (often named like NAME.NNNNgf) and was transferred/downloaded completely.
  2. Regenerate the font with METAFONT if you control the source, then re-run gftype or gftopk.

FAQ

What does .gf mean in TeX/METAFONT?

It is METAFONT’s “generic font” bitmap output format (often created as NAME.NNNNgf), representing rasterized glyphs.

How do I convert a .gf file to something TeX commonly uses?

Use gftopk to convert the GF (generic font) file into a PK (packed font) file: gftopk yourfont.gf yourfont.pk.

Can I use .gf directly in TeX?

Typically, TeX/DVI workflows use PK as the bitmap font format; GF is commonly converted to PK for use by DVI-reading programs.

Is .gf the same as a modern outline font like .otf or .ttf?

No. GF is a bitmap font output format from METAFONT, not an outline font format like OpenType or TrueType.

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